My 13 year old son is doing a science project. He is trying to develop a paper that analyzes the significance of different diameter drive wheels on steam locomatives regarding speed and hauling loads. Any ideas regarding sources he might check?
Thank you
Posted by hankmorris (Member # 1956) on :
Large diameter wheels found normally on passenger locomotives. Bigger the diameter, the faster you go. Traditionally, small wheels were for freight. Hope this helps.
------------------ Hank Morris, consulting editor National Railway Bulletin (NRHS)
Posted by atsf3751 (Member # 1538) on :
To elaborate a bit, yes, large-drivered locomotives were often used for passenger service, and large drivers were normally used for speed. However, as the steam era progressed, larger drivers became the norm.
For example, the 4-8-4 was designed as a dual-purpose locomotive, and many had very large drivers. Engines like 3751, 844, and 4449 all had 80-inch drivers and hauled both passenger and high speed freights. The Santa Fe had a class of 2-10-4 freight locomotives with 74-inch drivers, rather unusual for a strictly freight locomotive.
Most freight-only locomotives had drivers with diameters less than 70 inches. Speed was not a necessity but adhesion was, and larger drivers are prone to slipping under a heavy load.